Organic-vapor-induced Repeatable entrance and exit of C ₆₀ into/from single-wall carbon nanohorns at room temperature

We found that ethanol vapor forced C ₆₀ encapsulated inside single-wall carbon nanohorns (SWNHs) to exit from SWNHs at room temperature, and in reverse, toluene vapor forced the ejected C ₆₀ to re-enter. Interestingly, these entrance and exit behaviors were repeatable. Thermogravimetric analyses suggested C ₆₀-toluene pseudosolvate formation in internal hollow nanospaces of SWNHs. We consider the mechanism of the backand-forth transportations; the coincorporated toluene lured C ₆₀ from inside to outside SWNHs through adsorbed layers of ethanol formed on the SWNH surfaces. In the re-entrance, the toluene-adsorbed layer mediated transportation of C ₆₀ from outside to the most stable sites, that is, inside SWNHs.